Our prior research has indicated that parents of children undergoing hematopoietic stem cell transplant (HSCT) report significant levels of distress during HSCT hospitalization and that approximately twenty percent of parents report clinically-significant levels of distress one and a half years after transplant is complete. Our research has also evaluated the role of social and cognitive processes in parent distress and this work has identified social and cognitive processes that are important predictors of parents' long-term distress responses after pediatric HSCT. Based on this work and social and cognitive processing theory, we have developed a parent social-cognitive processing intervention (P-SCIP). Our pilot intervention trial indicated P-SCIP was efficacious and positively evaluated by parents. We will evaluate the efficacy of P-SCIP in reducing short- and long- term distress and parenting stress among 300 parents of children undergoing HSCT. P-SCIP will be delivered during the child's inpatient HSCT hospitalization and is specifically designed to improve parent social (e.g., sharing concerns) and cognitive (e.g., acceptance) processing of the transplant experience. The intervention includes five in-person sessions that are accompanied by an interactive CD-ROM. The CD-ROM complements the materials in the in-person sessions and provides parents with the opportunity to enhance and deepen their cognitive and social processing of the HSCT experience. In the proposed trial, we will develop the CD-ROM component of P-SCIP and then conduct a full-scale randomized clinical trial of P-SCIP. The intervention will be tested against best- practices psychosocial care (BPC) available in four enriched pediatric HSCT settings across the United States. P-SCIP will be provided to both Spanish- and English-speaking parents. Participants will complete measures of psychological distress, well-being, and social and cognitive processing at the time of HSCT, two, six and twelve months after HSCT. Research questions will address the effects of P-SCIP versus BPC on parent psychological adaptation and social and cognitive processing, as well as evaluate parent personal resources as well as child medical course variables that contribute to intervention response. We will also examine barriers to participation in the intervention by comparing barriers to participation among parents who refuse participation in the trial and parents who accept. The proposed study has clinical implications for improving the quality of life and the quality of care for parents of children undergoing HSCT as well as implications for the design of potentially effective and disseminable psychosocial interventions for parent caregivers of children with other physical illnesses. Relevance to Public Health Providing care for a child undergoing hematopoietic stem cell transplant (HSCT) is an extremely stressful experience. Our prior research indicates that between 20% and 30% of mothers providing primary care to their children during HSCT are diagnosed with either a depressive or anxiety-related disorder or experience moderate to severe symptoms of depression or anxiety at the time of transplant. Novel, efficacious, practical, and acceptable interventions to reduce parent distress during and after HSCT and prevent long-term, persistent traumatic stress are needed. Using cognitive and social processing theory, we have been able to identify key cognitive and social processes which contribute to distress reactions in a longitudinal observational study of a large group of parent caregivers. For the proposed study, we have used this information along with theory to guide the content of a Parent Social-Cognitive Processing Intervention Program (P-SCIP). P-SCIP incorporates in-person sessions with an interactive CD- ROM. We will evaluate the efficacy of P-SCIP in a randomized clinical trial of 300 parents of children undergoing HSCT.